This invention relates in general to a tool for removing an integrated circuit (IC) package from a circuit board or connector. In particular, the tool finds use in removing leaded IC packages of the dual inline package (DIP) type characterized by two rows of external connecting pins which are inserted either directly into a printed circuit board or into a connector mounted on a printed circuit board.
A number of integrated circuit extraction tools, such as those disclosed in U.S. Pat. No. 3,602,971 issued to William M. Halstead on Sept. 7, 1971, U.S. Pat. No. 3,757,406 issued to William Bezar on Sept. 11, 1973 and U.S. Pat. No. 3,797,092 issued to Norman S. Einarson on Mar. 19, 1974, have a generally plier-like appearance with the clamping ends having a number of slots for engaging the pins along the sidewalls of the integrated circuit package. Other extractors, such as those disclosed in U.S. Pat. No. 3,443,297 issued to Thomas K. Lusby, Jr. on May 13, 1969, U.S. Pat. No. 3,632,973 issued to James Edward O'Keefe on Jan. 4, 1972, U.S. Pat. No. 3,699,629 issued to Jesse C. Hood et al on Oct. 24, 1972 and U.S. Pat. No. 3,896,533 issued to Robert Ullman et al on July 29, 1975, have clamping ends which grasp the circuit package at its sides or ends. Either of these general types of extractors tend to be somewhat large and cumbersome so that gaining access to an individual circuit package on a densely populated circuit board is difficult.
Another type of extractor, such as that disclosed in U.S. Pat. No. 3,640,519 issued to William M. Halstead on Feb. 8, 1972, has an alligator-type clip configuration for engaging a plurality of the pins along the sidewalls of the package. While this type of extractor is somewhat smaller in size than the above-described types, sufficient space must be available along the sidewalls between packages to permit the opening of the clip jaws to engage the pins of the integrated circuit package.
Another type of extractor, such as that disclosed in U.S. Pat. No. 3,538,580 issued to Peter Martin Bruner on Nov. 10, 1970, has a relatively rigid frame which fits around an integrated circuit package to center working arms carrying teeth closed to grip the integrated circuit between the leads thereof.
In all of the extractors referred to above, the direction of the extraction force is wholly dependent upon the user. That is, if the user is unsteady, it is quite possible that the extraction force will be applied at an acute angle rather than perpendicularly. Should this occur, misalignment or possibly even irrepairable damage to the integrated circuit pins may result.
The extraction tool disclosed in U.S. Pat. No. 3,974,556 issued to Peter Steve Kubik on Aug. 17, 1976, provides an improvement over the previously discussed prior art. The tool has provision for converting a user applied compressive force into two components. One component actuates apparatus for grasping the underside of the integrated circuit package while the other component produces a nearly uniform perpendicular force on apparatus which straddles the integrated circuit package to effect the extraction. The extractor tool disclosed by Kubik has several limitations. It does not self center itself so as to insure that its hooks grasp the underside of the integrated circuit package about the center pin in each of the two rows of pins. Hence, if the user engages the tool about off-center pins, the tool will not apply an extraction force uniformly to the underside of the circuit package. This can result in the bending of pins as the circuit package would not be extracted with its horizontal plane parallel to the circuit board's horizontal plane. The inability to self-center can also result in the user engaging the hooks against rather than about the pins of the circuit package. This would most likely occur when extracting circuit packages whose pins are in contact with the circuit package sidewalls rather than being spaced away from the sidewalls, since with this type of circuit package the tool's legs cannot be aligned by passing them through the gaps between the pins.
The Kubik extraction tool only engages one pin on each sidewall of the circuit package and hence it appears incapable of extracting circuit packages having a large number of pins, such circuit packages requiring a relatively high extraction force.
Although the Kubik tool represents an advance over the prior art in being capable of applying a nearly perpendicular extraction force, it is still dependent on the user maintaining the tool's four legs on the circuit board surface as he applies compressive force to the tool. Failure of the operator to fulfill this requirement can result in misalignment of the circuit package's pins.
It is a general object of the present invention to provide a tool for removing integrated circuit packages from a circuit board or connector.
It is a further object of the present invention to provide an IC removal tool which applies a perpendicular extraction force without depending on the user maintaining proper tool positioning.
It is another object of the present invention to provide an IC removal tool which is self centering with respect to engaging itself about IC pins.
It is still another object of the present invention to provide an IC removal tool which applies a uniform extraction force at all points on the underside of the IC circuit package.
It is yet another object of the present invention to provide an IC removal tool capable of removing ICs having a relatively large number of pins.
Still further, it is an object of the present invention to provide an IC removal tool which limits the amount of compressive force applied to the pin populated sidewalls of an IC package so as to avoid damage to the pins during removal of the IC package.
These and other objects, features and advantages of the present invention will become more apparent from the detailed description of the preferred embodiment when read in conjunction with the drawings.